package com.wwzh.interview.study.thread;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantReadWriteLock;

class MyCache{
    private volatile Map<String,Object> map = new HashMap<>();
    private ReentrantReadWriteLock writeLock =  new ReentrantReadWriteLock();
    public void put(String key ,Object value){
        writeLock.writeLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + "\t 写入" + key + "===" + value);
            TimeUnit.MILLISECONDS.sleep(30);
            map.put(key,value);
            System.out.println(Thread.currentThread().getName() + "\t 写入完成" );
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            writeLock.writeLock().unlock();
        }
    }
    public void get(String key ){
        writeLock.readLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + "\t 去读" + key );
            TimeUnit.MILLISECONDS.sleep(30);
            System.out.println(Thread.currentThread().getName() + "\t 读取完成" + map.get(key) );
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            writeLock.readLock().unlock();
        }
    }

    public void clearMap(){
        map.clear();
    }
}

public class ReadWriteLockDemo {
    public static void main(String[] args) {
        MyCache myCache = new MyCache();

        for (int i = 0; i < 5; i++) {
            final int tempInt = i;
            new Thread(()->{
                myCache.put(tempInt +"",tempInt +"");
            },String.valueOf(i)).start();
        }
        for (int i = 0; i < 5; i++) {
            final int tempInt = i;
            new Thread(()->{
                myCache.get(tempInt +"");
            },String.valueOf(i)).start();
        }
    }
}
